This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The general area of research in our laboratory involves the biochemistry, enzymology and structural biology of bacterial enzymes implicated in antibiotic resistance, primarily those enzymes responsible for the deactivation of beta-lactam and aminoglycoside antibiotics. This proposal for beam time at SSRL focuses on the collection of high resolution diffraction data on native and mutant enzymes, and substrate/inhibitor complexes. The desire to collect data at SSRL is based upon our need for high quality, high resolution diffraction data from a number of different crystals, some of which diffract to atomic resolution, particularly in the case of the beta-lactamase enzymes. In addition, we are now producing the majority of our proteins as seleno-methionine derivatives, and we envisage an increased requirement for the collection of accurate MAD data.